JPH10147632A - Curing type tacky adhesive sheet and bonding of member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject sheet having sufficient initial tack in a normal state, capable of being readily cured by irradiation with light rays and surely bonding a member insufficient in heat resistance, by using a compound containing a specific epoxy group. SOLUTION: A composition comprising (A) a tacky polymer, (B) a compound containing an alicyclic epoxy group and (C) a cationic photopolymerization catalyst is formed. Preferably, the component A is an acrylic polymer formed by irradiating a polymerizable composition comprising a monomer component, an epoxy group-containing compound, a cationic photopolymerization catalyst and a radical photopolymerization initiator to be activated by light rays in a wavelength range of >=360nm with light rays in a wavelength range of >=360nm to subject the monomer above component to radical photopolymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable pressure-sensitive adhesive sheet and a method for joining members, and more particularly, to a curable pressure-sensitive adhesive sheet which is normally tacky and is cured by light irradiation. The present invention relates to an adhesive sheet and a method for joining members using the curable adhesive sheet.

[0002]

2. Description of the Related Art Acrylic pressure-sensitive adhesives have heat resistance, weather resistance,
Because of its excellent oil resistance, it is widely used for various adhesive processed products such as adhesive tape. However, the acrylic pressure-sensitive adhesive could not exhibit high peel resistance like the adhesive.

[0003] Therefore, a curable adhesive has been proposed which has both the easy workability of an acrylic pressure-sensitive adhesive and the high bonding strength and coating strength comparable to an adhesive. For example, JP-A-2-272076 discloses an adhesive tape using a pressure-sensitive thermosetting adhesive composed of a photopolymerizable composition containing an acrylate monomer and an epoxy resin.

When members are to be joined to each other using the adhesive tape described in the above-mentioned prior art, after irradiating the photopolymerizable composition with light to polymerize an acrylate monomer and develop adhesiveness, By sticking to an adherend and curing the epoxy resin by heating after sticking, a strong adhesive force can be obtained.

However, in the method described in JP-A-2-272076, since heat is used for curing the epoxy resin, a material having poor heat resistance cannot be used as the adherend. That is, there is a problem that the material of the adherend is limited.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a member which has a sufficient initial adhesive strength under normal conditions, can be easily cured by irradiating light, and can be used for a member having insufficient heat resistance. It is an object of the present invention to provide a curable pressure-sensitive adhesive sheet which can be bonded to a sheet and a method for bonding members using the curable pressure-sensitive adhesive sheet.

[0007]

Means for Solving the Problems Although not yet known, the inventors of the present application have previously described an acrylic polymer as a curable adhesive which can be used for joining members having insufficient heat resistance.
A curable adhesive sheet containing an epoxy resin and a compound which is exposed to light to induce ring opening of an epoxy group was proposed.
In this curable adhesive sheet, since the epoxy resin is cured by light irradiation, the adhesive can be applied to the adherend only by irradiating light before or after attaching the curable adhesive sheet to the adherend. The curable adhesive sheet can be firmly bonded, and the heat resistance of the adherend does not matter.

As a result of further study on a curable adhesive sheet which is cured by irradiating the light, it has been found that the curing time can be shortened by using a compound having a specific epoxy group. Reached.

That is, the curable adhesive sheet according to the first aspect of the present invention is obtained by molding a composition containing an adhesive polymer, a compound having an alicyclic epoxy group, and a cationic photopolymerization catalyst. It is characterized by becoming.

According to a second aspect of the present invention, in the curable adhesive sheet according to the first aspect,
The adhesive polymer comprises a monomer component, a compound having an alicyclic epoxy group, a photocationic polymerization catalyst,
A photo-polymerizable composition containing a photo-radical polymerization initiator activated by light in a wavelength region of at least nm is irradiated with light in a wavelength region of at least 360 nm to form the monomer component by photo-radical polymerization. Acrylic polymer.

[0011] In the curable adhesive sheet according to the first or second aspect of the present invention, preferably, the cationic photopolymerization catalyst comprises 30
It is a photocationic polymerization catalyst that is activated by being irradiated with light in a wavelength region of 0 nm or more and less than 360 nm.

According to a fourth aspect of the present invention, there is provided a method for joining members, which comprises curing before or after bonding the joining members together via the curable adhesive sheet according to any one of the first to third aspects. The mold adhesive sheet is irradiated with light having a wavelength of less than 360 nm and a light intensity of 5 mW / cm ² or more.

Hereinafter, the present invention will be described in detail. Adhesive Polymer In the present invention, the above-mentioned adhesive polymer is used to give an initial adhesive force to the curable adhesive sheet so that it can be used as an adhesive sheet.

The tacky polymer may be compatible with the compound having an alicyclic epoxy group and the cationic photopolymerization catalyst as long as it does not cause macrophase separation, and may be incompatible with the compound. There may be. Here, the macro phase separation refers to a phenomenon in which the adhesive polymer completely separates the phase with the compound having an epoxy group and the cationic photopolymerization catalyst, and any one of the adhesive polymer, the compound having an epoxy group, and the cationic photopolymerization catalyst. Or a state in which all are separated in a transparent state, and a state different from a state in which micro phase separation merely causes cloudiness.

The adhesive polymer which can be used in the present invention has been conventionally used to constitute an adhesive unless it causes macrophase separation with the compound having an epoxy group and the cationic photopolymerization catalyst as described above. Any suitable high molecular weight polymer can be used. Examples of such tacky polymers include acrylic polymers,
Polyesters, polyurethanes, silicones, polyethers, polycarbonates, polyvinyl ethers, polyvinyl chlorides, polyvinyl acetates, polyisobutylenes, and the like can be given. May be a copolymer containing a monomer as a main component.

The molecular weight of the adhesive polymer is preferably large, and the weight average molecular weight is preferably in the range of 100,000 to 5,000,000, more preferably 200,000 to 3,000,000, and further preferably 600,000 to 2,000,000. If the weight average molecular weight of the adhesive polymer is less than 100,000, the cohesive force of the curable pressure-sensitive adhesive sheet is insufficient, stringing may occur at the time of application, and peeling may occur. In some cases, the viscosity of the composition containing the polymer and the resin having an epoxy group becomes high, and the sheet cannot be formed.

Among the above-mentioned various polymers, acrylic polymers are used because they are commonly used as a main component of a pressure-sensitive adhesive in order to exhibit a superior initial adhesive strength and control of the adhesive properties is easy. Is preferred.

The structure of the acrylic polymer is not particularly limited, and may be, for example, a homopolymer structure, a random copolymer structure, a block copolymer structure, an alternating copolymer structure, a stereoregular structure, or a multibranched structure. , A star-shaped structure, a dendritic structure, a ladder structure, a ring structure, a helical structure and the like.

A more preferred example of the acrylic polymer is a polymer containing a unit composed of (meth) acrylic ester in an amount of 20% by weight or more in the acrylic polymer, wherein the alkyl group has 1 to 14 carbon atoms. A polymer or copolymer of the (meth) acrylate monomer (a) may be mentioned.

The above-mentioned copolymer includes an alkyl (meth) acrylate monomer (a) and a vinyl monomer (b) having an unsaturated bond copolymerizable with the alkyl (meth) acrylate monomer (a). And copolymers. The method for producing such a copolymer is not particularly limited, and it can be produced by a known method such as radical polymerization, anionic polymerization, coordination polymerization, or photopolymerization.

The alkyl (meth) acrylate monomer (a) includes methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-
Examples thereof include octyl (meth) acrylate, isononyl (meth) acrylate, and isomyristyl (meth) acrylate.

The vinyl monomer (b) is not particularly limited as long as it is a compound having an unsaturated bond copolymerizable with the alkyl (meth) acrylate monomer (a). In order to enhance the property, a vinyl monomer which is not reactive with the epoxy group contained in the curable adhesive sheet is preferable.

From the above viewpoint, it is not preferable to use a vinyl monomer having a carboxyl group such as acrylic acid or methacrylic acid, or a vinyl monomer such as maleic anhydride having an acid anhydride skeleton.

Examples of the vinyl monomer (b) include:
Examples thereof include (meth) acrylonitrile, N-vinylpyrrolidone, isovoltanyl (meth) acrylate, N-acryloylmorpholine, benzyl (meth) acrylate, glycidyl (meth) acrylate, N-vinylcaprolactone, and N-vinylpiperidine.

More preferably, an acrylic polymer obtained by subjecting a photopolymerizable composition containing an acrylic monomer to photoradical polymerization is used as the adhesive polymer. In this case, an acrylic polymer is obtained by photoradical polymerization by irradiating the photopolymerizable composition with light. Therefore, as described in claim 2, if the monomer component and the photoradical polymerization initiator are contained in the photopolymerizable composition together with the compound having an epoxy group and the photocationic polymerization catalyst, light is irradiated. Thereby, an acrylic polymer is formed, and the curable adhesive sheet according to the present invention can be easily obtained.

Further, by employing only a single method of irradiating light, a curable pressure-sensitive adhesive sheet can be obtained from the photopolymerizable composition, and a curable pressure-sensitive adhesive layer can be further obtained. Can also be cured. However, in this case, the light irradiated when forming the acrylic polymer by photoradical polymerization and the light irradiated when curing the curable adhesive sheet may have different wavelength ranges. is necessary.

Further, in order to induce a reaction for opening the epoxy group, larger energy is required than in the case of the photoradical polymerization. Therefore, more preferably, when the photoradical polymerization is performed, the photoradical polymerization is performed by irradiating light in a wavelength region of 360 nm or more, and a ring opening reaction of an epoxy group is induced to be cured. It is desirable to use light of this type.

The photo-radical polymerization initiator activated by light in a wavelength region of 360 nm or more includes 360 n
Compounds that must be activated by light having a wavelength of at least m and that do not cause energy transfer to the photocationic polymerization catalyst with light of less than 360 nm are preferred. Preferred examples of such a photo-radical polymerization initiator include:
For example, 4- (2-hydroxyethoxy) phenyl (2
-Hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, methoxyacetophenone, acetophenone derivative compounds such as 2,2-dimethoxy-2-phenylacetophenone; benzoin such as benzoin ethyl ether and benzoin propyl ether Ether compounds; ketal derivative compounds such as benzyl dimethyl ketal; halogenated ketones; acylphosphine oxides; acylphosphonates; bis- (2,6-dimethoxybenzoyl) -2,4,4-
Trimethylpentylphosphine oxide and the like can be mentioned.

Among the above examples of the photopolymerization initiator, in particular, 3
Acylphosphine oxide, acylphosphonate, bis- (2,6-dimethoxybenzoyl) -2, which has a high absorption coefficient for light in a wavelength region exceeding 60 nm.
4,4-Trimethylpentylphosphine oxide is preferred.

Examples of lamps used for light irradiation in the photoradical polymerization include low-pressure mercury lamps, medium-pressure mercury lamps,
A high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, and the like can be used.

Compound Having Epoxy Group The compound having an alicyclic epoxy group used in the curable adhesive sheet of the present invention undergoes ring-opening polymerization by the action of a photocationic polymerization catalyst when irradiated with light. It is used for curing a curable adhesive sheet.

In the curable adhesive sheet according to the present invention, the compound having an alicyclic epoxy group is used as described above. By using the compound having the alicyclic epoxy group, other epoxy group is used. The curing time can be reduced as compared with the case where a compound having the following formula is used.

The alicyclic epoxy resin is a compound having a cycloalkene oxide functional group.

[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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And the like. In the present invention, other than the compound having an alicyclic epoxy group, other epoxy group-containing compounds may be used in combination with the curable adhesive sheet. The epoxy group-containing compound used in this manner is not particularly limited as long as it has an epoxy group. Examples thereof include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolak type epoxy resin, a glycidyl ester-based compound, and glycidyl. Examples thereof include amine compounds.

Photocationic Polymerization Catalyst In the curable pressure-sensitive adhesive sheet of the present invention, curing proceeds by causing the epoxy group of the compound having an epoxy group to undergo a ring-opening reaction and polymerize. In order to induce the ring opening of the epoxy group, a photocationic polymerization catalyst is blended as described above, and the photocationic polymerization catalyst may be any arbitrary one that induces the ring opening of the epoxy group by irradiating light. Photocationic polymerization catalysts may be used.

Preferably, as described in claim 3, the photocationic polymerization catalyst has a size of 300 nm or more,
A material that is activated by being irradiated with light in a wavelength region of less than 0 nm is used. Since light having a wavelength of less than 360 nm is used, the energy intensity is high, and thus ring opening of the epoxy group can be rapidly advanced.

Examples of the above cationic photopolymerization catalyst include onium salts and organometallic complexes.
Examples of the onium salts include diazonium salts,
Sulfonium salts and iodonium salts can be mentioned. More specifically, for example, Optomer SP-150
Commercially available compounds such as (Asahi Denka Kogyo), Optomer SP-170 (Asahi Denka Kogyo), UVE-1014 (General Electronics), and CD-1012 (Sartomer) can be used. Examples of the organometallic complexes include, for example, an iron-allene complex, a titanocene complex, and an arylsilanol-aluminum complex.

The lamp used for the light irradiation includes:
Those having an emission distribution at a wavelength of 360 nm or less are used. For example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps,
A microwave excitation mercury lamp, a metal halide lamp, or the like can be used. In this case, in order to prevent curing of only the surface layer and realize internal curing, light having a wavelength of 320 nm or less may be cut and irradiated.

In the curable pressure-sensitive adhesive sheet according to the first aspect of the invention, the mixing ratio of the acrylic polymer and the compound having an epoxy group depends on the desired initial adhesive strength, adhesive strength after curing, and It is appropriately determined according to the adhesive force to the rough surface, and is not particularly limited, but preferably, the compound having an epoxy group is blended in an amount of 10 to 300 parts by weight with respect to 100 parts by weight of the acrylic polymer. . In this case, as the compound having an epoxy group, a compound having at least an alicyclic epoxy group is used as described above. For the mixing ratio of 10 to 300 parts by weight, only a compound having an alicyclic epoxy group is used. In some cases, the compound having an alicyclic epoxy group is 10 to 3
It is used in a ratio of 00 parts by weight, and when a compound having an alicyclic epoxy group and a compound having another epoxy group are used in combination, the compound is used such that the total of both becomes 10 to 300 parts by weight. .

The compounding ratio of the compound having an epoxy group is 1
If the amount is less than 0 parts by weight, even when cured by irradiating light, it may not be possible to obtain sufficient adhesive strength. In some cases, the initial adhesion may not be sufficiently obtained.

The proportion of the photocationic polymerization catalyst varies depending on the type thereof, and is not particularly limited. For example, 0.01 to 5 parts by weight based on 100 parts by weight of the compound having an epoxy group. It is preferred to be in the range of parts by weight. If the proportion of the cationic photopolymerization catalyst is less than 0.01 parts by weight, the ring opening reaction of the epoxy group may not be able to proceed sufficiently even when irradiated with light, and the adhesive curing with high adhesive strength may occur. Product may not be obtained, and even if compounded in excess of 5 parts by weight,
The effect of promoting curing does not increase any more, and conversely, the initial adhesive strength may decrease.

Other Additives In addition to the acrylic polymer, the compound having an epoxy group, and the cationic photopolymerization catalyst, the curable adhesive sheet according to the present invention may be any of known additives as long as the object of the present invention is not impaired. A tackifier resin, an extender and the like may be appropriately compounded.

For example, in order to improve the tackiness of the curable adhesive sheet of the present invention, a rosin resin, a modified rosin resin, a terpene resin, a terpene phenol resin, an aromatic modified terpene resin, a C5 or C9 series And a tackifier resin such as a petroleum resin and a chroman resin. Especially,
When the adherend is a polyolefin, a rosin-based resin and a petroleum resin are preferable in that a strong adhesive force can be exhibited.

For the purpose of improving coatability, thickeners such as acrylic rubber, epichlorohydrin rubber, isoprene rubber, and butyl rubber, thixotropic agents such as colloidal silica and polyvinylpyrrolidone, and increasing amounts of calcium carbonate, titanium oxide, clay and the like. An agent may be added.

Further, in order to provide a high-strength shear adhesive force when the adhesive sheet is formed, an inorganic hollow body such as a glass balloon, an alumina balloon, and a ceramic balloon; and an organic hollow body such as a nylon bead, an acrylic bead, and a silicon bead. Spherical bodies; organic hollow bodies such as vinylidene chloride balloons and acrylic balloons; and single fibers such as glass, polyester, rayon, nylon and cellulose may be added.

When the above glass fibers are blended, it is possible to add fibrous chips to the composition. High shear strength can be obtained.

Production of Curable Adhesive Sheet The method for producing the curable adhesive sheet according to the present invention is not particularly limited, and various methods such as a hot melt method, a casting coating method, and a UV polymerization method can be used. For example, in the casting coating method, the above-mentioned adhesive polymer, a compound having an epoxy group and a cationic photopolymerization catalyst are blended, and a resin composition obtained by adding a tackifier resin or the like as necessary is appropriately used. The method of molding into a sheet by the method, or the UV polymerization method, includes the above monomer component for obtaining an acrylic polymer by photoradical polymerization, a photoradical polymerization initiator, a compound having an epoxy group, and a photocationic polymerization catalyst The photopolymerizable composition is formed into a sheet, and the acrylic monomer is irradiated with light before or after the molding to irradiate the acrylic monomer. And a method in which the local polymerized acrylic polymer, may be any appropriate method.

Preferred examples of the production of the curable pressure-sensitive adhesive sheet according to the present invention by the above-mentioned UV polymerization method include:
Alkyl (meth) having 1 to 14 carbon atoms in the alkyl group
Acrylate monomer, vinyl monomer having an unsaturated bond copolymerizable with an alkyl (meth) acrylate monomer, a photo-radical polymerization initiator activated by light in a wavelength region of 360 nm or more, and a compound having an alicyclic epoxy group And a photopolymerizable composition prepared by mixing a photocationic polymerization catalyst that induces a ring-opening reaction of an epoxy group when irradiated with light having a wavelength of 300 nm to 360 nm.
A method for producing a curable adhesive sheet formed by irradiating light in a wavelength region exceeding 0 nm to form an acrylic polymer in a sheet by photoradical polymerization is used.

The cured adhesive sheet obtained in this manner contains a compound having an epoxy group and 300 to 360.
The photocationic polymerization catalyst that induces the ring opening reaction of the epoxy group with light having a wavelength of nm remains unreacted.

Therefore, immediately before or after laminating the curable adhesive sheet, it can be easily cured by irradiating light having a wavelength of 300 to 360 nm. For example, the epoxy group content in the sheet before irradiation with light having a wavelength of 300 to 360 nm is 0.0001 to
When a curable pressure-sensitive adhesive sheet of 0.01 mol / g is obtained, it varies depending on the wavelength and intensity of light to be irradiated, but when the conversion of epoxy groups is 0 to 30% immediately after irradiation, 7% at 25 ° C.
After curing for days, the conversion of epoxy groups in the sheet is 50
-100%.

Usage Form of Curable Adhesive Sheet The curable adhesive sheet according to the present invention is used as it is, for example, when bonding a bonding member to an adherend so as to be interposed and bonded therebetween. May be used in the form of a double-sided pressure-sensitive adhesive tape, or may be formed as a pressure-sensitive adhesive layer on at least one surface of a suitable substrate such as a synthetic resin film or cloth.

Examples of the substrate include various nonwoven fabrics such as rayon or cellulose, films or sheets made of various synthetic resins such as polyethylene, polyester, cellophane, polypropylene, polystyrene, and polyimide; foamed polyethylene, urethane foam, and neoprene foam. , Various foams such as polyvinyl chloride, resin plates made of various synthetic resins such as polystyrene, ABS, acrylic, polypropylene, and polyethylene, steel, stainless steel,
Sheets or plates made of various metals such as copper and aluminum, glass, wood, paper, cloth, and the like can be used.
There is no particular limitation. Further, the shape of the substrate is not limited to a thin shape such as a sheet or a plate, and may be any shape such as a prism, a rod, a sphere, and a shape having an aspheric surface.

[0061] In the bonding method according to claim 4 joining method of members according to the invention according to the member, the joining member via the adhesive and pressure-sensitive adhesive sheet according to any one of claims 1 to 3 described above to the adherend Before or after laminating, the curable adhesive sheet is cured by irradiating light. In this case, preferably,
"Before bonding" means before bonding and before curing of the resin having an epoxy group is completed by light irradiation. By giving activation energy,
When the curing of the compound having an epoxy group is completed, the curable pressure-sensitive adhesive sheet becomes too hard, and a sufficient initial adhesive strength may not be obtained.

In addition, as described in claim 4, preferably, it has a wavelength of less than 360 nm and a light intensity of 5 mW.
/ Cm ² or more is used. Light having a wavelength exceeding 360 nm does not have sufficient energy intensity, and may require a long time for curing. Similarly, when light having a light intensity of less than 5 mW / cm ² is used, similarly, a long time is required for curing. It may be.

When the curing member is irradiated with light before the joining member is joined to the adherend and the curing of the curable adhesive sheet is advanced, the joining member and the adherend are not irradiated with light. Further, it is possible to prevent the deterioration of the joining member and the adherend due to light. Therefore, when joining an adherend or a joining member that is likely to be deteriorated by light irradiation, it is desirable to irradiate the curable adhesive sheet in advance with light as described above. Further, when one of the adherend and the bonding member is easily deteriorated by light and the other is hardly deteriorated by light, the light is irradiated by bonding a curable adhesive sheet to the other member side, Thereafter, it may be bonded to the one member.

[0064] In the adhesive and pressure-sensitive adhesive sheet according to the action the present invention can be easily applied to an adherend to have a sufficient initial adhesive strength by the adhesive polymer. In addition, by irradiating light before or after the application to the adherend, the photocationic polymerization catalyst is activated to cause ring-opening polymerization of the compound having an epoxy group, thereby giving a strong adhesive cured product. Therefore,
The curable adhesive sheet is firmly joined to the adherend.

Further, in the present invention, a compound having an alicyclic epoxy group is used as the compound having an epoxy group. In the compound having an alicyclic epoxy group, the ring opening of the epoxy group is performed by another epoxy group. Since the reaction proceeds more quickly than the compound having the above, the curing time after light irradiation is shortened.

[0066]

The present invention will be clarified by the following non-limiting examples.

(Example 1) A 4 L separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet was charged with 2
-Ethylhexyl acrylate (2EHA) 36 g, N
-84 g of vinylpyrrolidone and 98 g of ethyl acetate were charged, and dissolved oxygen was removed by bubbling this monomer mixed solution with nitrogen gas for 20 minutes. Thereafter, the inside of the separable flask system was replaced with nitrogen gas, and the temperature was raised with stirring to reach reflux. After reaching reflux, 1,1-di (t-hexylperoxy) is used as a polymerization initiator.
0.024 g of -3,3,5-trimethylcyclohexane
Was diluted with 1 g of ethyl acetate, and the solution was added to the system.
Then, one hour later, 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added.
A solution obtained by diluting 036 g with 1 g of ethyl acetate was added. Further, 2 hours, 3 hours, and 4 hours after the initiation of the polymerization.
After an hour, a solution was prepared by diluting 0.048 g, 0.12 g and 0.36 g of di (3,5,5-trimethylhexanoyl) peroxide with 1 g of ethyl acetate, respectively. Seven hours after the first addition of the polymerization initiator, an acrylic copolymer having a weight average molecular weight of about 500,000 was obtained.

Acrylic copolymer 1 obtained as described above
To 00 g, 30 g of an epoxy resin (bisphenol A type epoxy group resin, trade name: Rica Resin BEO-60), 40 g of glycidyl methacrylate, epoxy resin (bisphenol A type epoxy group resin, trade name: Epicoat 82)
8) 25 g, alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Ltd.
Trade name: 5 g of celloxide 2081 (corresponding to the structural formula of (5) exemplified above, n = 1), 1.0 g of a photocationic polymerization catalyst (trade name: SP-170, manufactured by Asahi Denka Kogyo KK),
And 0.1 g of a photo-radical polymerization initiator (trade name: I-170, manufactured by Ciba-Geigy) was blended to obtain a photo-polymerizable composition.

The above photopolymerizable composition is coated on a polyethylene terephthalate film whose surface has been release-treated,
It was dried in a dryer at 100 ° C. for 2 minutes to obtain a curable adhesive sheet having a thickness of 300 μm supported by a polyethylene terephthalate film.

The above curable pressure-sensitive adhesive sheet is 25 mm × 25 mm
mm, cut into a 25 mm wide, 100 mm long and 2 mm thick stainless steel plate (made of SUS304,
Hereinafter, the adherend A is abbreviated. ), 300nm or more,
After irradiating the sheet with light having a light intensity of less than 350 nm of 25 mW / cm ² for 60 seconds to peel off the polyethylene terephthalate film, another adherend A is stuck thereon, and a shear adhesive strength measurement test is performed. I got a piece.

Using the above-mentioned test piece for measuring shear adhesive strength and test piece for measuring T-peel force, shear adhesive strength 5 minutes after bonding and shear adhesive strength after curing at 25 ° C. for 3 days, and After curing at 25 ° C. for 7 days,
Each was measured according to JIS Z0237. Table 1 below shows the composition of the curable pressure-sensitive adhesive sheet and the evaluation results of the shear adhesive strength.

(Examples 2 to 4) A curable adhesive sheet was obtained in the same manner as in Example 1 except that the composition of the photopolymerizable composition was changed as shown in Table 1 below. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 1 To 100 g of the acrylic copolymer prepared in Example 1, 1.0 g of a cationic photopolymerization catalyst (manufactured by Asahi Denka Kogyo Co., Ltd., trade name: Optomer SP-170) and an epoxy resin (oiling shell) 36 g of Epoxy 828 (trade name, manufactured by Epoxy Co., Ltd.) was charged and stirred to obtain a uniform photopolymerizable composition. Using the above photopolymerizable composition, a test piece for measuring the shear adhesive strength was prepared in the same manner as in the examples, and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 2 100 g of the acrylic copolymer prepared in Example 1 and 1.0 g of a cationic photopolymerization catalyst (trade name: Optomer SP-170, manufactured by Asahi Denka Kogyo KK)
36 g of an epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epikote Rika Resin BEO-60E),
A photopolymerizable composition was obtained. Using the above photopolymerizable composition, a curable pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, and further evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0075]

[Table 1]

In Table 1, GMA indicates glycidyl methacrylate.

[0077]

The curable pressure-sensitive adhesive sheet according to the first aspect of the present invention contains a tacky polymer, a compound having an alicyclic epoxy group, and a photocationic polymerization catalyst, and thus is more sufficiently coated with the tacky polymer. Not only can it be easily adhered to the adherend because of its initial adhesive strength, but also the curing proceeds with the photocationic polymerization catalyst of the compound having an epoxy group after light irradiation, so that the adhesive strength to the adherend is effectively increased Enhanced. Further, since the curing proceeds using light as described above, the curable pressure-sensitive adhesive sheet according to the present invention can be suitably used for an adherend or a bonded body having low heat resistance, and further, a press or the like. Since a strong adhesive force is exhibited without the need for curing under a pressure load, the present invention can be applied to a joining member which is deformed under pressure curing conditions. Further, since the compound having the alicyclic epoxy group is used, the curing time after light irradiation can be shortened, so that the working steps can be shortened.

Further, in the curable pressure-sensitive adhesive sheet according to the present invention, at the time of application, the adhesive force and cohesive force that can be temporarily fixed by utilizing the initial adhesive force of the adhesive polymer are developed. In addition, the bonding process can be simplified, and the curable adhesive sheet has a high cohesive force and adhesive force, so that the bonding member is cut, bonded, and punched immediately after irradiation with light for curing. Even if such processing is performed, the joint portion itself is hardly affected.

According to a second aspect of the present invention, the curable adhesive sheet according to the first aspect further comprises a photo-radical polymerization initiator activated by light in a wavelength region of 360 nm or more. 360n for photopolymerizable composition
The acrylic polymer is formed by irradiating light in a wavelength region of m or more, so that a curable adhesive sheet can be easily obtained only by irradiating light after forming the photopolymerizable composition on a sheet. Can be. Therefore, a curable adhesive sheet can be efficiently produced.

According to the third aspect of the present invention, the cationic photopolymerization catalyst in the curable adhesive sheet has a thickness of 300 nm or more.
Since it is activated by being irradiated with light in a wavelength region of less than 60 nm, a compound having an epoxy group can be rapidly cured using light in a wavelength region of less than 360 nm having high energy intensity, and a curing type The adhesive strength of the adhesive sheet can be effectively increased.

In the method for joining members according to the fourth aspect, the curable adhesive sheet according to any one of the first to third aspects is applied to the member.
Light in the wavelength region with a high energy intensity of less than 60 nm,
Moreover, since the irradiation is performed so that the light intensity becomes 5 mW / cm ² or more, the curing of the curable adhesive sheet proceeds rapidly, and the joining members can be firmly and easily joined to each other.

Claims (4)

[Claims] 1. A curable pressure-sensitive adhesive sheet obtained by molding a composition containing an adhesive polymer, a compound having an alicyclic epoxy group, and a cationic photopolymerization catalyst. 2. The photopolymerization wherein the adhesive polymer comprises a monomer component, a compound having an epoxy group, a photocationic polymerization catalyst, and a photoradical polymerization initiator activated by light in a wavelength region of 360 nm or more. 360 to the acidic composition
The curable adhesive sheet according to claim 1, wherein the curable adhesive sheet is an acrylic polymer formed by radiating light in a wavelength region of not less than nm and subjecting the monomer component to photoradical polymerization. 3. The photocationic polymerization catalyst according to claim 1, wherein the
The curable pressure-sensitive adhesive sheet according to claim 1, which is a photocationic polymerization catalyst that is activated by being irradiated with light in a wavelength region of less than 360 nm. 4. A light in a wavelength region of less than 360 nm is applied to the curable adhesive sheet before or after bonding the bonding members together via the curable adhesive sheet according to claim 1. And irradiating light having a light intensity of 5 mW / cm ² or more.